Christian Bale is showing off a bald patch and a paunch after undergoing a drastic transformation for his latest film role.

The Dark Knight star has been spotted looking unrecognisable on the set of the new untitled David O. Russell movie alongside his The Fighter co-star Amy Adams.

Bale is seen sporting greasy hair with a bald patch, a beard and a much bulkier frame.

The actor's latest movie makeover comes after he shed the pounds for his Oscar-winning turn as drug-ravaged boxer DICky Eklund in O. Russell's 2010 drama The Fighter.

Bale's most famous transformation was for 2004's The MAChinist, when he lost a shocking 62 pounds (28 kilograms) to play a chronic insomniac.